Quantitative ultrasound measurements of bone: measurement error, discordance, and their effects on longitudinal studies.
D000368:Aged; D000369:Aged, 80 and over; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D002111:Calcaneus; D005260:Female; D016330:Frail Elderly; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010024:Osteoporosis / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography